An aerial view of the area around the town of Orte, near Rome, where homes and infrastructures were damaged by flood water Tuesday. / Giuseppe Palozzi, AP

by Eric J. Lyman, Special for USA TODAY

by Eric J. Lyman, Special for USA TODAY

ROME â?? Three days of heavy rains and winds have left large parts of northern and central Italy under water Tuesday, turning streets into canals and causing the collapse of a bridge as utility workers drove across.

The three employees of the utility company Enel were en route to reconnect power near Grosetto, in Tuscany, when the bridge they were driving over in Umbria collapsed into the fast-moving water below. Their car plunged into the water, and they were confirmed dead.

Hundreds of people were forced to flee their homes as rivers burst their banks and streets were flooded. Some were rescued from rooftops by helicopters.

A fourth fatality was an elderly man whose car was swept away near the Tuscan city of Capalbio. Another half-dozen people remained missing.

The rains tapered off Tuesday, and water levels began to drop. Venice reported its sixth-highest flood level since record-keeping began in 1872.

The dropping water levels come after tourists were filmed swimming across Venice's famous St. Mark's Square on Monday. Around two-thirds of the city remained under water, some of it waist-deep.

"I have never seen anything like it," Orbetello Mayor Monica Paffetti told Italian television. "There are stories about big floods in the past, but nothing like this."

Orbetello, in western Tuscany, was inundated. The city's streets transformed into canals and about 800 people fled their homes in the nearby village of Albinia. Thousands were left without electricity.

The rains caused the soil in a rural cemetery in coastal Tuscany to erode, exposing several caskets and prompting health concerns.

Nine inches of rain fell in just four hours in Tuscany, overflowing the Parmignola and Ricortola rivers. The Po River also nearly overflowed. In the Massa Carrara region in Tuscany, a couple in their car were swept away but then rescued by police and neighbors.

Parts of the highway between Rome and Florence were closed because of flooding for the first time since the 1980s. Rail lines between Orbetello and Grosetto were closed.

The Tiber River, which runs through the center of Rome, overflowed bike and jogging paths along its banks in the capital, though it did not cause any flooding because of high seawalls in the city. Some railway lines and roads leading into the city from the north were closed.

Farther up the coast, the tourist villages of Cinque Terre, in Liguria, were severely damaged. Residents of the towns, which can be reached by foot or by boat, were worried that their homes may collapse into the sea after rains eroded the foundations, according to Italian news media.

The cash-strapped Italian government was scrambling to find emergency funds. The European Union earmarked $23 million in "solidarity funds" to help with repairs to roads, electrical systems, water and sewage systems and building controls.